[terryl1]

Serum immunofixation vs. urine immunofixation

by terryl1 on Sat Oct 06, 2012 5:21 pm

I have light chain only myeloma...20% of MMers. My SPEP's are always normal--no traditional M-Spike. My disease is tracked primarily by the FLC assay and also by serum and urine immunofixation (IFE). I am in a clinical trial at the NIH utilizing carfilzomib/rev/dex for newly diagnosed. At baseline in April, my kappa FLC's were 16,000mg/l and the ratio was 12,000...no kidding. After five cycles, they have plummeted to 130mg/l with a ratio of 26. My blood counts are all normal now. In April, my hemoglobin was in the 8's, now it's 14.0 or so. I am in VGPR. The strange thing is for two months the serum IFE has been normal and it has been noted that "no anomalous immunoglobulins detected". However, the urine IFE notes "kappa light chains detected". My doctor says this happens occasionally but usually in the reverse order. Has anyone ever seen such results like this or have any insights? Thanks. Terry L.

[Dr. Peter Voorhees]

Re: Serum immunofixation vs. urine immunofixation

by Dr. Peter Voorhees on Fri Oct 12, 2012 2:53 am

Serum free light chain testing is the most sensitive way of measuring light chain disease. This will be the last test to revert to normal, but you are getting close! A 24-hour urine protein immunofixation would be the next most sensitive. Then the serum immunofixation. Then the serum protein electrophoresis. So, I am not surprised that the serum immunofixation is now normal but the other tests remain abnormal. The bottom line is that things are moving dramatically in the right direction!

Keep up the good work!

Pete V.

[terryl1]

Re: Serum immunofixation vs. urine immunofixation

by terryl1 on Fri Oct 12, 2012 2:14 pm

Hi Dr. Voorhees, thanks for the detailed response! Terry

[zephyrus]

Re: Serum immunofixation vs. urine immunofixation

by zephyrus on Thu Jun 27, 2013 2:58 pm

Dr. Peter Voorhees wrote:
> Serum free light chain testing is the most sensitive way of measuring light
> chain disease. This will be the last test to revert to normal, but you are
> getting close! A 24-hour urine protein immunofixation would be the next
> most sensitive. Then the serum immunofixation. Then the serum protein
> electrophoresis. So, I am not surprised that the serum immunofixation is
> now normal but the other tests remain abnormal. The bottom line is that
> things are moving dramatically in the right direction!
>
> Keep up the good work!
>
> Pete V.
My wife is in a very similar situation (light chain myeloma) as Pete except that her FLC has been normal for about 6 months. UPEP, SPEP and serum immunofixation all show no paraproteins, however, like Pete, the urine immunofixation shows evidence of Bence-Jones proteins. I thought this was a very sensitive test even though it is not quantitative.